With latest technology, this H4 40W 3000-6000K Waterproof Dual LED Headlamps + Ballasts is waterproof and impact resistant so as to prolong its service time. Xenon lamp, made into non-filament style, has longer lifespan than other lamps. Additionally, the headlamp is much brighter than ordinary ones. Overall, it is a great replacement or a spare for you. Most electronic devices utilize an electrical ballast to limit the amount of current in an electric circuit. If you want to install a ballast, you should not miss our recommendation here!